# US 4,394,664 A · Thermal plotter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,394,664 A - Document ID: US4394664A - Status: Granted - Kind: A - Application number: 06/344,021 - Filed: 1982-01-29 - Granted: 1983-07-19 - Earliest claimed: 1982-01-29 - Assignees: Laitram, L.L.C. - Inventors: James M. Lapeyre - Web page: https://patentgrep.com/patent/US4394664A ## CPC - G01D 15/10: Heated recording elements acting on heatsensitive layers - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract A thermal plotter is provided which is of extremely simple construction and which can provide a magnified trace on a sheet in response to very small mechanical movement. A pair of spaced electrically conductive bus bars are disposed with their forward edges in contact with an electrical resistance wire which is maintained at a small acute angle to the axis of the bus bars. The resistance wire is supported by a mechanism which is moveable about a pivot axis to cause lateral movement of the portion of the resistance wire which bridges the bus bars. Small pivotal movement of the mechanism is magnified by the angular orientation of the resistance wire and bus bars into relatively larger movement along the length of the bus bars. A heat sensitive sheet is disposed with a surface in engagement with the confronting edges of the bus bar and bridging resistance wire, and is arranged for movement along a path transverse to the axis of the bus bars. An electrical potential is applied to the bus bars to cause current flow through the bridging portion of the resistance wire and the heating thereof. The heated wire is operative to cause formation of a visible image on the confronting sheet in a pattern corresponding to movement of the bridging portion. ## Claims ### Claim 1 A thermal plotter comprising: a pair of electrically conductive elements spaced from each other and disposed along a first axis; an electrical resistance wire disposed at an acute angle to said first axis of said elements and having a bridging portion in contact with the front edges of the elements; means for supporting the resistance wire at an acute angle to said first axis and operative to move the wire along a second axis transverse to the first axis, and to cause movement of the bridging portion of the wire along the front edges of said elements; means coupled to the support means for causing movement of the wire along the second axis in response to an input; means for providing a voltage across said elements; a thermally responsive sheet disposed in contact with the front edges of the elements; the bridging portion of the wire being heated by electrical current flowing therethrough to a temperature sufficient to produce a visible image on the sheet; the movement of the bridging portion of the wire along said elements being magnified in relation to movement of the wire along the second axis. ### Claim 2 (depends on 1) The thermal plotter of claim 1 wherein said means coupled to the support means is a transducer operative in response to an electrical signal to cause movement of the wire along the second axis. ### Claim 3 (depends on 1) The thermal plotter of claim 1 wherein the means coupled to the support means is a transducer operative in response to a mechanical force to cause movement of the wire along the second axis. ### Claim 4 (depends on 1) The thermal plotter of claim 1 wherein said electrically conductive elements are in parallel spaced relationship along the first axis, the spacing between the elements and the length of the bridging portion, defining the spot size of the image which can be formed on the sheet. ### Claim 5 (depends on 1) The thermal plotter of claim 1 wherein the thermally responsive sheet is disposed for movement along an axis transverse to the first axis. ### Claim 6 (depends on 1) The thermal plotter of claim 1 wherein said means for supporting the resistance wire includes a mechanism for movement of the wire about a pivot axis. ### Claim 7 (depends on 6) The thermal plotter of claim 6 wherein the mechanism includes a pivot axis parallel to the first axis and spaced therefrom. ### Claim 8 A thermal plotter comprising: a pair of electrically conductive elements spaced from each other and disposed along a first axis; a support assembly including a pivot rod supported for rotation about a pivot axis, and arms outwardly extending from the pivot rod and rotatable therewith; an electrical resistance wire extending between and supported by the outward ends of the support arms; said resistance wire being disposed at an acute angle to said first axis of said elements, and having a bridging portion in contact with the front edges of the elements; means coupled to the support assembly for causing rotation thereof about the pivot axis in response to an input condition; the movement of the resistance wire causing linear movement of the bridging portion of the wire along the front edges of said elements; means for providing a voltage across said elements to cause current flow through the bridging portion of the resistance wire and heating of the bridging portion to a temperature sufficient to cause activation of the thermally responsive sheet; and a thermally responsive sheet disposed in contact with the front edges of the elements and bridging portion of the resistance wire. ### Claim 9 (depends on 8) The thermal plotter of claim 8 wherein the voltage providing means is operative to provide pulsed power to said elements. ### Claim 10 A thermal plotter comprising: a pair of electrically conductive elements spaced from each other and disposed along a first axis; an electrical resistance wire disposed at an acute angle to said first axis of said elements and having a bridging portion in contact with the front edges of the elements; means for supporting the resistance wire and electrically conductive elements with the resistance wire at an acute angle to said first axis and operative to provide relative movement between the wire and elements along a second axis transverse to the first axis, thereby to cause movement of the bridging portion of the wire along the front edges of said elements; means coupled to the support means for causing movement of the wire along the second axis in response to an input; means for providing a voltage across said elements; a thermally responsive sheet disposed in contact with the front edges of the elements; the bridging portion of the wire being heated by electrical current flowing therethrough to a temperature sufficient to produce a visible image on the sheet; the movement of the bridging portion of the wire along said elements being magnified in relation to movement of the wire along the second axis.